Ubuntu - Check Tensorflow version

Run:

python -c 'import tensorflow as tf; print(tf.__version__)'  # for Python 2
python3 -c 'import tensorflow as tf; print(tf.__version__)'  # for Python 3

Note that python is symlinked to /usr/bin/python3 in some Linux distributions, so use python instead of python3 in these cases.
pip list | grep tensorflow for Python 2 or pip3 list | grep tensorflow for Python 3 will also show the version of Tensorflow installed.

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Virtualenv installation

Run:

python -c 'import tensorflow as tf; print(tf.__version__)'  # for both Python 2 and Python 3

pip list | grep tensorflow will also show the version of Tensorflow installed.
For example, I have installed TensorFlow 0.9.0 in a virtualenv for Python 3. So, I get:

$ python -c 'import tensorflow as tf; print(tf.__version__)'
0.9.0

$ pip list | grep tensorflow
tensorflow (0.9.0)

Reference

https://stackoverflow.com/questions/38549253/how-to-find-which-version-of-tensorflow-is-installed-in-my-system